The Boston Celtics turned consecutive games against teams they’re jockeying with for playoff positioning into a notice for the rest of the Eastern Conference: They have every intention of breaking off a postseason run. Kevin Garnett scored 20 points and Rajon Rondo dished out double-digit assists for his 17th consecutive game, finishing with 15 to help lead Boston to a 103-79 win over the struggling Philadelphia 76ers on Sunday night.